Adult acquired flatfoot deformity or posterior tibial tendon dysfunction is a gradual but progressive loss of a person's arch. The posterior tibial muscle is a deep muscle in the back of the calf that has a long tendon that extends from above the ankle and attaches into several sites around the arch of the foot. This muscle acts like a stirrup on the inside of the foot to help support and stabilize the arch and to create a rigid platform for walking and running If the posterior tibial tendon becomes damaged or tears, then the arch loses its stability and collapses causing a flatfoot. There are various stages of the adult flatfoot deformity. At stage two, deformities usually require a surgical bone procedure to recreate the arch and stabilize the foot. These procedures include isolated fusion procedures, bone grafts, and/or the repositioning of bones through bony cuts called osteotomies.
Various osteotomies for correction of the adult flatfoot have been developed and practiced. One such osteotomy, the Evans procedure, is a calcaneal osteotomy that lengthens the lateral column and realigns the midtarsal joint by reducing forefoot abduction. The Evans procedure also plantarflexes the first metatarsal and reduces talocalcaneal subluxation. Another osteotomy, the Cotton procedure, corrects the flatfoot deformity through a structural graft placed in the medial cuneiform. In both the Evans and Cotton procedures, a bone graft or implant is placed in an osteotomy created in the foot of a patient. Bone implants, such as the CANCELLO-PURE™ Evans and Cotton bone wedges available from Wright Medical Technology, Inc., in Arlington, Tenn., have been created for use in both types of osteotomies. As the size and shape of the foot varies from person to person, it is sometimes necessary for a bone implant to be customized in the operating room (OR) so that the implant appropriately corrects the deformity. However, customizing a bone implant, during a surgical procedure is not easily accomplished as the bone implants are often formed from sterilized animal bone or allograft making them difficult to shape tableside.